According to a recent trend of high output and high efficiency engines, an engine adopting a gasoline direct injection (GDI) method, which directly injects fuel into a cylinder, has been widely adopted.
A GDI engine and a TGDI engine, in which a turbocharger is applied to a GDI engine, have a problem in that particulate matter (PM) is produced due to an increase in an incomplete combustion section within a combustion chamber.
In order to solve the production of the PM, research and development, such as an application of a gasoline particulate filter (GPF) serving as an exhaust particulate filter used in a diesel engine, has been actively conducted.
The GPF commonly combusts soot with natural regeneration unlike a diesel filter, and a temperature of an operation is mostly 400° C. or higher, so that when the soot is filtered, the soot regeneration is immediately performed.
When the filter is checked after the completion of actual endurance of 160,000 KM, the amount of soot is very small (0.1 g) and the amount of ash is large (20 g).
Ash, which is a final product of the soot, is a main cause of an increase in back pressure when mileage is increased. In a case of the natural regeneration of the GPF, a phenomenon occurs in which the ash blocks a wall surface.
However, in a diesel filter, a temperature and pressure are sharply increased during the regeneration by forcible regeneration through post injection, so that the ash is accumulated at a rear side of the filter.
The absolute amount of soot of the diesel is large, so that the amount of ash is large compared to gasoline.
Accordingly, in a case of the GPF, a back pressure is increased due to the ash stacked on the wall surface of the filter, and as a result, an output deteriorates and the amount of fuel consumed is increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.